scholarly journals PLEKHA5, PLEKHA6 and PLEKHA7 bind to PDZD11 to target the Menkes ATPase ATP7A to the cell periphery and regulate copper homeostasis

2021 ◽  
Author(s):  
Sandra Citi ◽  
Sophie Sluysmans ◽  
Isabelle Mean ◽  
Tong Xiao ◽  
Amina Boukhatemi ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Copper Homeostasis ◽  
Cell Periphery ◽  
Ww Domains ◽  
C Terminus ◽  
Menkes Atpase ◽  
Junctional Protein ◽  
Cellular Copper ◽  
And Function

Copper homeostasis is crucial for cellular physiology and development, and its dysregulation leads to disease. The Menkes ATPase ATP7A plays a key role in copper efflux, by trafficking from the Golgi to the plasma membrane upon cell exposure to elevated copper, but the mechanisms that target ATP7A to the cell periphery are poorly understood. PDZD11 interacts with the C-terminus of ATP7A, which contains sequences involved in ATP7A trafficking, but the role of PDZD11 in ATP7A localization is unknown. Here we identify PLEKHA5 and PLEKHA6 as new interactors of PDZD11, which similarly to the junctional protein PLEKHA7 bind to PDZD11 N-terminus through their WW domains. Using CRISPR-KO kidney epithelial cells, we show by immunofluorescence that WW-PLEKHAs (PLEKHA5, PLEKHA6, PLEKHA7) recruit PDZD11 to distinct plasma membrane localizations, and that they are required for the efficient anterograde targeting of ATP7A to the cell periphery in elevated copper. Pulldown experiments show that WW-PLEKHAs promote PDZD11 interaction with the C-terminus of ATP7A. However, WW-PLEKHAs and PDZD11 are not necessary for ATP7A Golgi localization in basal copper, ATP7A copper-induced exit from the Golgi, and ATP7A retrograde trafficking to the Golgi. Finally, measuring bioavailable copper with the labile copper probe CF4 shows that WW-PLEKHAs and PDZD11 are required to maintain low intracellular copper levels when cells are exposed to elevated copper. These data indicate that WW-PLEKHAs-PDZD11 complexes regulate the localization and function of ATP7A to modulate cellular copper homeostasis.

scholarly journals PLEKHA5, PLEKHA6 and PLEKHA7 bind to PDZD11 to target the Menkes ATPase ATP7A to the cell periphery and regulate copper homeostasis

2021 ◽  
Author(s):  
Sophie Sluysmans ◽  
Isabelle Méan ◽  
Tong Xiao ◽  
Amina Boukhatemi ◽  
Flavio Ferreira ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Copper Homeostasis ◽  
Cell Periphery ◽  
Ww Domains ◽  
C Terminus ◽  
Menkes Atpase ◽  
Junctional Protein ◽  
Cellular Copper ◽  
And Function

Copper homeostasis is crucial for cellular physiology and development, and its dysregulation leads to disease. The Menkes ATPase ATP7A plays a key role in copper efflux, by trafficking from the Golgi to the plasma membrane upon cell exposure to elevated copper, but the mechanisms that target ATP7A to the cell periphery are poorly understood. PDZD11 interacts with the C-terminus of ATP7A, which contains sequences involved in ATP7A trafficking, but the role of PDZD11 in ATP7A localization is unknown. Here we identify PLEKHA5 and PLEKHA6 as new interactors of PDZD11, which bind to PDZD11 N-terminus through their WW domains similarly to the junctional protein PLEKHA7. Using CRISPR-KO kidney epithelial cells, we show by immunofluorescence microscopy that WW-PLEKHAs (PLEKHA5, PLEKHA6, PLEKHA7) recruit PDZD11 to distinct plasma membrane localizations, and that they are required for the efficient anterograde targeting of ATP7A to the cell periphery in elevated copper conditions. Pulldown experiments show that WW-PLEKHAs promote PDZD11 interaction with the C-terminus of ATP7A. However, WW-PLEKHAs and PDZD11 are not necessary for ATP7A Golgi localization in basal copper, ATP7A copper-induced exit from the Golgi, and ATP7A retrograde trafficking to the Golgi. Finally, measuring bioavailable and total cellular copper, metallothionein-1 expression and cell viability shows that WW-PLEKHAs and PDZD11 are required to maintain low intracellular copper levels when cells are exposed to elevated copper. These data indicate that WW-PLEKHAs-PDZD11 complexes regulate the localization and function of ATP7A to promote copper extrusion in elevated copper.

Extracellular vesicle interplay in cardiovascular pathophysiology

2021 ◽  
Author(s):  
Sherin Saheera ◽  
Vivek P Jani ◽  
Kenneth W Witwer ◽  
Shelby Kutty
Keyword(s):  
Plasma Membrane ◽  
Cardiovascular System ◽  
Lipid Bilayer ◽  
Cellular Responses ◽  
Extracellular Vesicle ◽  
Cargo Proteins ◽  
And Function ◽  
Intercellular Communications ◽  
Rna And Dna

Extracellular vesicles (EVs) are nanosized lipid bilayer-delimited particles released from cells that mediate intercellular communications and play a pivotal role in various physiological and pathological processes. Subtypes of EVs may include plasma-membrane ectosomes or microvesicles and endosomal-origin exosomes, although functional distinctions remain unclear. EVs carry cargo proteins, nucleic acids (RNA and DNA), lipids, and metabolites. By presenting or transferring this cargo to recipient cells, EVs can trigger cellular responses. Here, we summarize what is known about EV biogenesis, composition, and function, with an emphasis on the role of EVs in cardiovascular system. Additionally, we provide an update on the function of EVs in cardiovascular pathophysiology, further highlighting their potential for diagnostic and therapeutic applications.

Role of the C-Terminus of the High-Conductance Calcium-Activated Potassium Channel in Channel Structure and Function

Biochemistry ◽  
2005 ◽  
Vol 44 (30) ◽  
pp. 10135-10144 ◽  
Author(s):  
William A. Schmalhofer ◽  
Manuel Sanchez ◽  
Ge Dai ◽  
Ashvin Dewan ◽  
Lorena Secades ◽  
...  
Keyword(s):  
Potassium Channel ◽  
Structure And Function ◽  
Channel Structure ◽  
C Terminus ◽  
And Function ◽  
Calcium Activated Potassium Channel ◽  
High Conductance

Cellular copper homeostasis: current concepts on its interplay with glutathione homeostasis and its implication in physiology and human diseases

Metallomics ◽  
2017 ◽  
Vol 9 (10) ◽  
pp. 1376-1388 ◽  
Author(s):  
Ashima Bhattacharjee ◽  
Kaustav Chakraborty ◽  
Aditya Shukla
Keyword(s):  
Trace Element ◽  
Copper Homeostasis ◽  
Human Diseases ◽  
Living Organisms ◽  
Cellular Copper ◽  
Almost All ◽  
Glutathione Homeostasis ◽  
Intracellular Copper

Copper is a trace element essential for almost all living organisms, however the level of intracellular copper needs to be tightly regulated. This review explores the existing literature on the role of glutathione in regulating cellular copper homeostasis.

scholarly journals Nbr1 Is a Novel Inhibitor of Ligand-Mediated Receptor Tyrosine Kinase Degradation

2010 ◽  
Vol 30 (24) ◽  
pp. 5672-5685 ◽  
Author(s):  
Faraz K. Mardakheh ◽  
Giulio Auciello ◽  
Tim R. Dafforn ◽  
Joshua Z. Rappoport ◽  
John K. Heath
Keyword(s):  
Tyrosine Kinases ◽  
Protein Localization ◽  
Negative Regulator ◽  
Receptor Internalization ◽  
C Terminus ◽  
Late Endosomes ◽  
Exact Function ◽  
Α Helix ◽  
And Function

ABSTRACT Neighbor of BRCA1 (Nbr1) is a highly conserved multidomain scaffold protein with proposed roles in endocytic trafficking and selective autophagy. However, the exact function of Nbr1 in these contexts has not been studied in detail. Here we investigated the role of Nbr1 in the trafficking of receptor tyrosine kinases (RTKs). We report that ectopic Nbr1 expression inhibits the ligand-mediated lysosomal degradation of RTKs, and this is probably done via the inhibition of receptor internalization. Conversely, the depletion of endogenous NBR1 enhances RTK degradation. Analyses of truncation mutations demonstrated that the C terminus of Nbr1 is essential but not sufficient for this activity. Moreover, the C terminus of Nbr1 is essential but not sufficient for the localization of the protein to late endosomes. We demonstrate that the C terminus of Nbr1 contains a novel membrane-interacting amphipathic α-helix, which is essential for the late endocytic localization of the protein but not for its effect on RTK degradation. Finally, autophagic and late endocytic localizations of Nbr1 are independent of one another, suggesting that the roles of Nbr1 in each context might be distinct. Our results define Nbr1 as a negative regulator of ligand-mediated RTK degradation and reveal the interplay between its various regions for protein localization and function.

Role of the C-terminus and the long cytoplasmic loop in reduced folate carrier expression and function

2002 ◽  
Vol 63 (9) ◽  
pp. 1717-1724 ◽  
Author(s):  
Iraida G. Sharina ◽  
Rongbao Zhao ◽  
Yanhua Wang ◽  
Solomon Babani ◽  
I.David Goldman
Keyword(s):  
Reduced Folate Carrier ◽  
Cytoplasmic Loop ◽  
C Terminus ◽  
And Function

scholarly journals C-terminus of the P4-ATPase ATP8A2 functions in protein folding and regulation of phospholipid flippase activity

2017 ◽  
Vol 28 (3) ◽  
pp. 452-462 ◽  
Author(s):  
Madhavan Chalat ◽  
Kody Moleschi ◽  
Robert S. Molday
Keyword(s):  
Endoplasmic Reticulum ◽  
Atpase Activity ◽  
Deletion Mutants ◽  
Serine Residue ◽  
Cellular Processes ◽  
Phospholipid Asymmetry ◽  
C Terminus ◽  
And Function ◽  
Phospholipid Flippase

ATP8A2 is a P4-ATPase that flips phosphatidylserine and phosphatidylethanolamine across cell membranes. This generates membrane phospholipid asymmetry, a property important in many cellular processes, including vesicle trafficking. ATP8A2 deficiency causes severe neurodegenerative diseases. We investigated the role of the C-terminus of ATP8A2 in its expression, subcellular localization, interaction with its subunit CDC50A, and function as a phosphatidylserine flippase. C-terminal deletion mutants exhibited a reduced tendency to solubilize in mild detergent and exit the endoplasmic reticulum. The solubilized protein, however, assembled with CDC50A and displayed phosphatidylserine flippase activity. Deletion of the C-terminal 33 residues resulted in reduced phosphatidylserine-dependent ATPase activity, phosphatidylserine flippase activity, and neurite extension in PC12 cells. These reduced activities were reversed with 60- and 80-residue C-terminal deletions. Unlike the yeast P4-ATPase Drs2, ATP8A2 is not regulated by phosphoinositides but undergoes phosphorylation on the serine residue within a CaMKII target motif. We propose a model in which the C-terminus of ATP8A2 consists of an autoinhibitor domain upstream of the C-terminal 33 residues and an anti-autoinhibitor domain at the extreme C-terminus. The latter blocks the inhibitory activity of the autoinhibitor domain. We conclude that the C-terminus plays an important role in the efficient folding and regulation of ATP8A2.

scholarly journals Role of the N-terminal transmembrane domain in the endo-lysosomal targeting and function of the human ABCB6 protein

2015 ◽  
Vol 467 (1) ◽  
pp. 127-139 ◽  
Author(s):  
Katalin Kiss ◽  
Nora Kucsma ◽  
Anna Brozik ◽  
Gabor E. Tusnady ◽  
Ptissam Bergam ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Transmembrane Domain ◽  
Intracellular Localization ◽  
Atp Binding ◽  
Multivesicular Bodies ◽  
Molecular Dissection ◽  
Terminal Domain ◽  
Lysosomal Targeting ◽  
And Function

The intracellular localization of ATP-binding cassette, sub family B (ABCB) 6 is a matter of debate. We show that ABCB6 is internalized from the plasma membrane to multivesicular bodies and lysosomes. Molecular dissection of the ABCB6 protein reveals a role of its N-terminal domain in targeting.

scholarly journals C Terminus of Nce102 Determines the Structure and Function of Microdomains in the Saccharomyces cerevisiae Plasma Membrane

2010 ◽  
Vol 9 (8) ◽  
pp. 1184-1192 ◽  
Author(s):  
Martin Loibl ◽  
Guido Grossmann ◽  
Vendula Stradalova ◽  
Andreas Klingl ◽  
Reinhard Rachel ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Plasma Membrane ◽  
Protein Trafficking ◽  
Ultrastructural Feature ◽  
Membrane Topology ◽  
Content Type ◽  
C Terminus ◽  
Composition And Structure ◽  
And Function ◽  
Arginine Permease

ABSTRACT The plasma membrane of the yeast Saccharomyces cerevisiae contains stably distributed lateral domains of specific composition and structure, termed MCC (membrane compartment of arginine permease Can1). Accumulation of Can1 and other specific proton symporters within MCC is known to regulate the turnover of these transporters and is controlled by the presence of another MCC protein, Nce102. We show that in an NCE102 deletion strain the function of Nce102 in directing the specific permeases into MCC can be complemented by overexpression of the NCE102 close homolog FHN1 (the previously uncharacterized YGR131W) as well as by distant Schizosaccharomyces pombe homolog fhn1 (SPBC1685.13). We conclude that this mechanism of plasma membrane organization is conserved through the phylum Ascomycota. We used a hemagglutinin (HA)/Suc2/His4C reporter to determine the membrane topology of Nce102. In contrast to predictions, its N and C termini are oriented toward the cytosol. Deletion of the C terminus or even of its last 6 amino acids does not disturb protein trafficking, but it seriously affects the formation of MCC. We show that the C-terminal part of the Nce102 protein is necessary for localization of both Nce102 itself and Can1 to MCC and also for the formation of furrow-like membrane invaginations, the characteristic ultrastructural feature of MCC domains.

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